For example, X-ray workers and Y-ray workers in mechanical industrial systems belong to special types of work, which are toxic and harmful.
Whether it belongs to a special type of work depends on the list of special types of work approved by the former Ministry of Labor before 1993 and formulated by the competent department of your industry. What is in the list is a special type of work, and what is not in the list is not a special type of work.